atm, there isnt much advantage of AM2. in some cases 939 actually outperformed it.
however, due to it beeing DDR2 compartible, it run's on lower voltages, and stay's cooler. also, the AM2 chips consume less power than their s939 counterparts ( except the 3800+, they are even)
end.. like said, AMD's future CPU's will be on socket AM2, not 939
When they run at 1.22v rather then 1.35v-1.4v they should run a little cooler. One article seen at the end of august supports that with the review on the AM2 4600+ EE seen at
http://techgage.com/article/amd_am2_4600_ee
Here's what one ad for an AM2 complete build had to say on AM2 over 939.
Advanced power-user multi-screen workstation
AMD dual-core Athlon 64 X2 processor</SPAN>
– Socket AM2 architecture*
– Up to 87% faster than AMD Athlon 64
– Faster than all Intel Pentium 4 / Pentium D processors
– Optional top-of-line dual-core
AMD Athlon 64 FX62
Microsoft Windows XP Professional SP2
– System is certified for
Windows Vista
– Optional dual-boot upgrade:
Windows XP Professional x64 Edition Dual-core AMD Athlon 64 X2 processor
– AMD Athlon 64 X2 4200+ (2.2 GHz, 2x 512K L2 cache)
– Option:
Athlon 64 X2 4600+ (2.4 GHz, 2x 512K L2 cache)
– Option:
Athlon 64 FX62 (2.8 GHz, 2x 1MB L2 cache)
http://www.digitaltigers.com/stratosphere-titan.php
The main problem about AM2 boards regarding power demands won't be from the cpu but the larger number of memory slots. Once you start packing dimms in to increase memory to 8gb or even 16gb the demand on power goes up along with it. You gain with the cpu but lose on the memory side ot it.